There is a need to provide electric power which is economical and reliable. There is also a need to provide electric power from sources of energy which are not dependent themselves on electric power to run component parts thereof but can also operate on electric grid in case of a failure of their own electrical power operating system. There is also the need to provide electric power during periods of transmission line power failures whereby to maintain electrically-dependent equipment operative. There is also a need to recover energy loss through exhaust combustion products of fuel-fired boilers, for example and to convert to reusable energy.